I just finished Flash Boys by Michael Lewis. It's a description of how Wall Street screws pretty much everyone, how it was detected, why the SEC protects THEM, and what happened when someone tried to fight back. Good book, highly recommend for anyone into tech or econ/finance.
Before that was Panic by the same author, which was a collection of essays about the financial panics since 1987. Also good, if you're into that sort of thing.